Pipetting systems are well known, and typically are used in laboratories and hospitals for the aspiration and dispensing of relatively small, predetermined quantities of liquids into the wells of plates such as microplates or deep well blocks or the like. Examples of the liquids being dispensed include blood, other biological samples, solvents, reagents and the like. Liquid is normally drawn by suction from one set of plates or the like and subsequently released into the wells of other plates or the like. Typically, pipette tips are used to draw some or all of the fluid from one set of wells in a plate or reservoir and transfer it to another set of wells in another plate.
For high volume, automated systems, the spacing of the wells in one set of plates is the same as the spacing of the wells in the plates to which the fluid is being transferred. However, not all plates have the same well spacings, and not all plates have the same number of wells. Therefore, it is desirable to be able to vary the number of pipette tips, or the spacing between tips in such automated systems. Such flexibility is essential in most laboratories and hospitals. It is also desirable to be able to perform such operations rapidly and to be able to perform a high volume of operations in a very short period of time.
Many preexisting, automated, high volume systems are available and include those shown in U.S. Pat. Nos. 4,830,832, 6,148,878 and 5,988,236. Examples of hand held, non-automated pipetters are disclosed in U.S. Pat. Nos. 5,061,449, 4,824,642, 5,057,281, and 5,104,621.
Another known high throughput, automated pipetter was sold by Matrix Technologies, Inc. and Jenoptik Bioinstruments GmbH (now known as Cybio AG) of Jena, Germany under the trademarks JOBI-WELL and CYBI-WELL. In this system, liquid in so-called “mother plates” is transferred to other plates which are called “daughter plates.” The mother plates are stacked vertically on one side of a stacking mechanism and are removed sequentially and transported to a pipetting head which removes liquid from the mother plates. These mother plates are then returned to a different side of the same stacking mechanism. Empty daughter plates are retrieved from one part of a stacking mechanism for the daughter plates and are transported to the pipetting head. The plate is then lifted up to the pipetting head for the dispensing of liquid previously retrieved from the mother plates. These filled daughter plates are then returned to a different part of the daughter plate stacking mechanism. These systems include features such as ink jet printers, bar code readers, different pipetting head configurations for different sized tips, different numbers of tips with different spacings, stacking mechanisms for both shallow well and deep well plates and tip wash stations.
Other automated systems are sold by Tomtec, 1000 Sherman Avenue, Hamden, Conn. 06451 and by Cosmotec Ltd. of Tokyo, Japan in which the pipetter utilizes stackers for the microplates. Both products are capable of handling microplates having different numbers of wells or different spacings between the wells.